共查询到20条相似文献,搜索用时 453 毫秒
1.
To actually reflect the seismic temporal-spatial inhomogeneity of intra continental strong earthquakes of North China in seismic
hazard analysis, several seismological and geological characteristics have been selected and quantized to describe the seismicity
features in time and space of every magnitude interval with the thought of dividing the interesting magnitude range into several
intervals and using of spatial probability distribution function. A component analysis method with orthogonal transformation
is introduced to avoid the repeated use of the same element and the subjective effects in determining the annual earthquake
occurrence rates of earthquake. By passing synthetic fuzzy judgement on the nonintercorrelated new characteristics, the annual
occurrence rates of every magnitude interval of each potential source area are obtained associated with the adjustments of
earthquake reducing process after the occurrence ofM>7 quake. An intensity map of the Beijing-Tianjin-Zhangjiakou area is calculated as an example which shows a close coincidence
with the seismic temporal-spatial inhomogeneity of North China.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,13, 496–504, 1991. 相似文献
2.
In this paper, one of the distribution-free tests — randomization test, is briefly described. It doesn’t need any distribution
assumption and its related parameter estimation and is applicable to random and nonrandom sample. Then it is used to the test
of migration of strong earthquakes on the Xianshuihe Fault Belt and “immunity” of large earthquakes in the large northern
reigon of China. The test results show that there is 98.7% confidence degree for the migration of strong earthqueks on the
Xianshuihe Fault Belt and “immunity” of earthqueks withM
S⩾8 toM
S⩾7 is significant in the large northern region of China. The obtained test results and the test method itself have certain
application in the practice.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,15, 484–489, 1993. 相似文献
3.
Ming Yan 《地震学报(英文版)》1992,5(1):11-22
A method is proposed in this paper for the analysis of temporal and spatial characteristics of composite nodal plane solutions
for small earthquakes. With this method, the interested region is devided into small areas according to the geological features
of the region. As an example, 107 composite nodal plane solutions are calculated for the adjoining region of Shaxi, Hebei
and Neimenggu. The temporal and spatial characteristics of the variations of the solution parameters before and after the
great Tangshan main earthquake in 1976 have been analysed and some interesting results are obtained.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismlogica Sinica,13, 9–20, 1991. 相似文献
4.
The intterrelation among strong earthquakes and its application are emphatically studied in this paper. Taking North China
seismic region as study area, we have investigated how a great earthquake influence other strong earthqukaes in neighbouring
area? Does there exist earthqukae immunity phenomenon? If it exists, what distributional pattern did it has in space-time
domain? The results show that occurrence of earthquakes withM⩾7 has cetain immunity phenomenon to earthquakes withM⩾6 in North China. Among others, the immunity area of earthquakes withM=8 is much larger than that ofM=7. For earthquakes withM⩾8, the immunity area to the earthquakes ofM=7 is larger than toM=6.
Based on the above analysis, using some statistical methods, we gave the variational regularity of seismic immunity factor
with space and time, and explored its concrete application in seismic hazard analysis.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,15, 339–346, 1993. 相似文献
5.
In this paper, on the basis of intensity data from 85 earthquakes occurred in China, the method of resolving overdetermined
equations by using the damped least squares method is applied to inversing for the mean value of 1 s. S wave quality factor,
the spreading factor and the S-wave acceleration at the foci of earthquakes in 7 regions of China. The relation between S-wave
acceleration at the foci of earthquakes and magnitude is discussed. As an example, 2-DQ
S distribution in Taiwan Province is obtained by inversion. It is found that there exists some corresponding relation between
this distribution and Bouguer gravitational anomaly and seismicity.
Preliminary analysis and discussion on results of the inversion, and estimation of error inQ
S are made.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,13, 202–211, 1991.
The English version of this paper is improved by Professor Yushou Xie. 相似文献
6.
Yushou Xie 《地震学报(英文版)》1992,5(3):635-646
The earthquakes offshore Fujian and Guangdong Provinces concentrated along the two segments near Nan’ao in the south and Quanzhou
in the north of the off coast fault, which is very active since the late Pleistocene. In 1918 and 1906, two earthquakes with
magnitudes 7.3 and 6.1 respectively occurred in the south and the north regions. With the instrumentally determined seismic
parameters of these two earthquakes as standards, the author evaluated the parameters of the historical earthquakes by comparing
their macroseismic materials with consideration of the geological background. As a result, chronological tables of historical
earthquakes of the south and the north regions were compiled.
The seismic activity of the two regions synchronized basically, and their strongest recorded earthquakes were both aroundM
s 7.3. Seismic activity usually intensified before the occurrence of strong events. Aftershocks were frequent, but strong aftershocks
usually occurred one to several years after the main shock. Two high tides of seismic activity occurred since the late 15th
century. Around 1600, eight earthquakes each with magnitudes over 4.3 occurred in both of the two regions. The magnitude of
the strongest shock in the south region is 6.7, that in the north region is 7.5. The second high tide occurred at the early
20th century. Among the 18 earthquakes occurred in the south region, one was of magnitude 7.3; whilst only two earthquakes
with magnitudes 6.1 and 5.5 respectively occurred in the north region. Further, medium to strong earthquakes never occurred
since 1942. Whether this is the “mitigation effect” of strong shocks, or a big earthquake is brewing in the north region is
worth intensive study.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,13, 505–515, 1991.
This work is supported by Chinese Joint Seismological Science Foundation. 相似文献
7.
Xue-Ze Wen 《地震学报(英文版)》1993,6(4):993-1004
Spatial distribution of sources of strong and large earthquakes on the Xiaojiang fault zone in eastern Yunnan is studied according
to historical earthquake data. 7 segments of relatively independent sources or basic units of rupture along the fault zone
have been identified preliminarily. On every segment, time intervals between main historical earthquakes are generally characterized
by “time-predictable” recurrence behavior with indetermination. A statistic model for the time intervals between earthquakes
of the fault zone has been preliminarily established. And a mathematical method has been introduced into this paper to reckon
average recurrence interval between earthquakes under the condition of having known the size of the last event at a specific
segment. Based on these, ranges of the average recurrence intervals given confidence have been estimated for events of various
sizes on the fault zone. Further, the author puts forward a real-time probabilistic model that is suitable to analyze seismic
potential for individual segments along a fault zone on which earthquake recurrence intervals have been characterized by quasi-time-predictable
behavior, and applies this model to calculate conditional probabilities and probability gains of earthquake recurring on the
individual segments of the Xiaojiang fault zone during the period from 1991 to 2005. As a consequence, it has shown that two
parts of this fault zone, from south of Dongchuan to Songming and from Chengjiang to Huaning, have relatively high likelihoods
for strong or large earthquake recurring in the future.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,15, 322–330, 1993. 相似文献
8.
Yebang Xu 《地震学报(英文版)》1992,5(2):389-398
The research of the information dimension (D
1) in an active fault zone considers the contribution of each seismic event to information and reflects the characteristics
of the temporal and spatial distributions of earthquakes from a new point of view, avoiding some short-comings of the research
about the capacity dimension (D
0). The results of calculation show that the information dimension of the temporal distribution in Xianshuihe active fault
zone before Luhuo large earthquake isD
1=0.1051. It is a consult creterion of large earthquakes in future in the fault zone. The information dimensions of the temporal
distribution of the earthquakes in Anninghe active fault zone are respectivelyD
1(t
N)=0.1363 (for the north section) andD
1(t
S)=0.06710 (for the south section). The information dimensions of the spatial distribution are respectivelyD
1(K
N)=1.053 (for the north section) andD
1(K
S)=0.7758 (for the south section). The north section and the south section belong to two self-similar systems with different
information dimensions respectively. The extent of the self-organization of seismic activity in the south section is higher
than that in the north section. This is helpful for us to judge the major dangerous section in the key region of the seismic
monitoring. The research about the information dimension of the temporal and the spatial distributions of earthquakes is significant
for the exploration of active fault zones and seismic prediction.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,13, 372–379, 1991.
This paper is sponsored by the Chinese Joint Seismological Science Foundation. The English version is improved by Zhenwen
An. 相似文献
9.
Introduction The characteristics of generalized foreshock and direct foreshock and their identification,as well as their application to medium and short-term prediction of strong earthquake is a major study objective in seismometry both in China and abroad.China has made many short-term and imminent earthquake predictions.Among the ones with clear hazard-mitigating effect and social manifestation,direct foreshock has made an obvious contribution,for example,the MS=7.2Menglian earthquake occu… 相似文献
10.
How to test the reasonability of the seismic zoning map with probabilistic means is the most concerned problem. So far, there
were no good methods to test zoning map using actual intensity data. Firstly, the author suggest the concept of random field,
then proved that the average value of the randomifield is ergodic by using Monte Carlo method, therefor the spatial average
tend to be the average of the random field with probability of the zoning map. Thus, a method of testing seismic zoning map
with probabilistic means using spatial distributing samples of intensity caused by actual earthquakes was provided. The Chinese
seismic zoning map made in 1990 was tested using recent 15 years and 50 years intensity samples. The results shows that this
zoning map is reasonable. The method provided in this paper can be used in other circumstance in which random field methods
were used.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,15, 53–60, 1993. 相似文献
11.
In this paper we outlined the chaotic attractor of the precursory field evolution of the seismogenic system and its fractal
dimension of the precursory time and space distribution. We developed the calculative method of reconstruction complex system
dynamics from single time series and analysed the descent dimension phenomena of the precursory distribution before large
earthquakes. We also showed the time-space synthesis method constructed complex system dynamics by many stations or many methodes
in the seismogenic system consists of large area tectonic network. This method can describe the self-organization behavior
of the system more accurately and get rid of the uncertainty and randomness caused by single station or single method. As
an example, we calculated the chaotic attractor of the precursory field evolution and the fractal dimension of the precursory
time and space distribution and its change tendencies before large earthquakes in Beijing-Tianjing area.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,15, 463–469, 1993. 相似文献
12.
Shao-Xie Xu 《地震学报(英文版)》1993,6(2):517-533
The method of prediction of earthquake by using seismisity (MPES) is to make use of the message of earthquakes (including
large, middle, small) in pre-period to predict large earthquake in post-period. Some better methods are presented in this
paper which are selected among many means used in our country recent years. These methods are classified into six sets: 1.
Method of spatial pattern; 2. Method of time process; 3. Method of seismic sequence; 4. Method of earthquake correlation;
5. Method of parameters of seismic source and medium; 6. Comprehensive method. Prediction effects of each method are evaluated
with unique score. The value of each method, scoreR, are generally in a range between 0.3 and 0.6. This value only represents internal consistency, however, the ability of actual
prediction belongs to the extensional effect, which is generally lower than the value of internal consistency. If the ability
of actual prediction could be evaluated withR = 0.3, the ability of prediction of earthquake by seismicity will be stated as following: If most of earthquakes must be
predicted, the warning time needs to take seventy percent of whole time period of prediction; If half earthquakes must be
predicted, the warning time needs to take twenty percent of whole time period of prediction.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,15, 239–252, 1993. 相似文献
13.
This paper aims to analyse the geoelectrical resistivityρ
s
data on the dipole electrode sounding, which were firstly accumulated from the earthquake prone region in China. The analyses
on the one order difference value of the geoelectrical resistivity indicated that, firstly, more than 4 percent of theρ
s
data reveals the precursors by 3 to 76 days ahead the earthquakes occurring, with the magnitude range of 4 ≤M ≤ 6. 4, in a region of 100 km around the station, and secondly, the results revealed that the seasonal variation ofρ
s
data were slight.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,14, 211–219, 1992. 相似文献
14.
Tectonic forces from the relative movements between plates are transmitted into the continental crust, and then they create
the earthquake generating stress field there. The space-time distribution of the seismic activity including the small earthquakes
in a region reflects the variation of the stress field in the region.
According to this idea, the characteristics of the stress fields in the various regions of East Asia have been analyzed in
detail in this paper based on a lot of solutions of focal mechanisms and data of seismic activity during the last 500 years.
The results indicate that the tectonic forces from the subduction of the Pacific Ocean plate underneath the Eurasian plate
control the stress field in the region from North China to the northern part of the North-South Seismic Belt.
The variation of the regional stress field shown by the variation of seismic activity in some regions of Japan has also been
discussed based on characteristics of variation of the seimicity of small earthquakes.
Synchronous variations of seismicity in the past 100 years or so in West China and in the boundary region between the Indo-Australian
and Eurasian plates implicate that there is the transmission of tectonic forces into West China through the collision between
the Indo-Australian and Eurasian plates. The active seismic activity in the boundary region between the Indo-Australian and
the Eurasian plates and in West China is continuing consistently.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,13, 287–294, 1991. 相似文献
15.
In the light of the rheological properties of crustal rocks and some features of earthquakes, a rheological model for fault
rocks is suggested in the paper and the possibility of applying the suggested model to the study of earthquake mechanism is
discussed. The results show that it is reasonable to take the suggested model as a physical simplification of fault rocks
and to apply it to the numerical calculation and simulation of 2-D problems.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,14, 129–136, 1992. 相似文献
16.
Moment tensors of eleven major earthquakes in the Tibetan Plateau and its surrounding region from 1966 to 1980 are estimated
by generalized inverse technique. The seismic source time function and focal depth are immediately determined in the inversion.
The results show that moment tensors of some events differ significantly from double couple, the deviation increases with
decreasing plunge angle of null axis. All these events occurred in the upper crust, much shallower than those reported so
far, for example, in NEIS Bulletin. Focal mechanism solution obtained from the moment tensors are consistent with the idea
that the Indian plate collides northwards with the Eurasian plate and that an eastward spreading exists in the crust of the
Tibetan Plateau. The stress drops for earthquakes of intraplate are systematically higher than those of earthquakes in suture
zone. The source process duration becomes longer with seismic moment, but for the same seismic moment, the process duration
for earthquakes in suture zone is about 1.4 times of those for intraplate event, these results suggest that the earthquakes
near suture zone may be of a special characteristics in source process differently from those in intraplate.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,14, 423 – 434, 1992. 相似文献
17.
According to geological tectonics and seismic activites this paper devided North China (30°–45°N, 105°–130°E) into four areas.
We analyzed the North China earthquake catalogue from 1970 to 1986 (from 1965 to 1986 for Huabei, the North China, plain region)
and identified forty-two bursts of aftershock. Seven of them occurred in aftershock regions of strong earthquakes and seventeen
of them in the seismic swarm regions. The relation between strong earthquakes with the remaining eighteen bursts of aftershocks
has been studied and tested statistically in this paper. The result of statistical testing show that the random probabilityp of coincidence of bursts of aftershock with subsequent strong earthquakes is less than six percent. By Xu’sR scoring method the efficacy of predicting strong earthquake from bursts of aftershock is estimated greater than 39 percent.
Following the method proposed in the paper we analyzed the earthquake catalogue of China from 1987 to June, 1988. The results
show that there was only one burst of aftershock occurred on Jan. 6, 1988 withM=3.6 in Xiuyan of Northeast China. It implicates that a potential earthquake withM
S⩽5 might occur in one year afterwards in the region of Northeast China. Actually on Feb. 25, 1988 an earthquake withM
S=5.3 occurred in Zhangwu of Northeast China. Another example is Datong-Yanggao shock on October 18, 1989 which is a burst
of aftershock. Three hours after an expected shock withM =6.1 took place in the same area. Two examples above have been tested in practical prediction and this shows that bursts
of aftershocks are significant in predicting strong earthquakes.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,13, 273–280, 1991.
Part of earthquake catalogue is from Jinbiao Chen, Peiyan Chen and Quanlin Li. 相似文献
18.
This paper has introduced the method of self-similarity analysis of time series into the analysis and study of earthquake
sequence, and then researched its application in earthquake prediction. As parameter of earthquake time series, we can take
the cumulated sum of the numbers of equivalent earthquakesQ=ΣN*, the numbers of equivalent earthquakeN*, maximum magnitudeM
max, average magnitudeQ=ΣN*, and the difference ΔN* between the numbersN* in two adjacent time intervals. The given method may be applied to analysis of long-period seismic sequences in different
regions as well as to anlysis of seismic sequence in the aftershock region of strong earthquake. For making quantitative analysis
the coefficient of self-similarity of earthquake sequence in order of timeμs was introduced. The results of self-similarity analysis were obtained for the earthquake sequences in North China, West South
China, the Capital region of China, and for the East Yamashi region of Japan. They show that in period or half year to several
years beforeM⩾7.0 andM⩾6.0 earthquakes occurred in these regions separately, the self-similarity coefficientμs calculated by using the above-mentioned parameters had remarkably anamalous decrease variations. The duration time ofμs anomaly depends on the earthquake magnitude and may be different from different regions. Therefore, the self-similarity coefficient
in order of timeμs can be considered as a long-medium term precursory index.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,15, 455–462, 1993. 相似文献
19.
发震构造特性是潜在震源区划分及其地震年发生率确定的重要依据。潜在震源区除了反映“未来具有发生破坏性地震的地区”的内涵外,还应反映高震级档地震具有相似复发特征的涵义。由于在地震活动性参数统计单元内,有一些具有不同本底地震的活动构造块体,为更好地反映地震活动的空间不均匀性,考虑潜在震源区的三级划分是有必要的。通过分析潜在震源区内高震级档地震的复发特征,计算预测时段内潜在震源区的高震级档地震的发震概率,采用预测时段内概率等效转换获得地震年平均发生率的方法,有助于在中国地震危险性分析框架内考虑潜在震源区的强震复发特性。另外,文中还对潜在震源区内特征地震次级震级档频度不足的特性和发震构造上强震非均匀性在地震危险性分析中的应用问题进行了探讨 相似文献
20.
According to the fracture mechanics rupture model of earthquakes put forward by us, several equations to compute tectonic
ambient shear stress value τ0 have been derived [equations (1), (2), (3), (5)]. τ0 values for intermediate and small earthquakes occurred in Chinese mainland and Southern California have been calculated by
use of these equations. The results demonstrate that the level and distribution of τ0 are closely related to the location where large earthquakes will occur, i.e. the region with higher level of τ0 will be prone to occur large earthquakes and the region with lower level will usually occur small earthquakes. According
to the spatial distribution of τ0, the seismic hazard regions or the potential earthquake source regions can in some degree be determined. According to the
variation of τ0 with time, the large earthquake occurrence time can be roughly estimated. According to the distribution of τ0 in Southern California and variation with time, three high stress level regions are determined, one (Goldfield area) of them
is the present seismic hazard region.
Contribution No. 98A02023, Institute of Geophysics, State Seismological Bureau, China 相似文献